Wideband Self-Adaptive RF Cancellation Circuit for Full-Duplex Radio: Operating Principle and Measurements

This paper presents a novel RF circuit architecture for self-interference cancellation in inband full-duplex radio transceivers. The developed canceller is able to provide wideband cancellation with waveform bandwidths in the order of 100 MHz or beyond and contains also self-adaptive or self-healing features enabling automatic tracking of time-varying self-interference channel characteristics. In addition to architecture and operating principle descriptions, we also provide actual RF measurements at 2.4 GHz ISM band demonstrating the achievable cancellation levels with different bandwidths and when operating in different antenna configurations and under low-cost highly nonlinear power amplifier. In a very challenging example with a 100 MHz waveform bandwidth, around 41 dB total cancellation is obtained while the corresponding cancellation figure is close to 60 dB with the more conventional 20 MHz carrier bandwidth. Also, efficient tracking in time-varying reflection scenarios is demonstrated.Comment: 7 pages, to be presented in 2015 IEEE 81st Vehicular Technology Conferenc

Signaalin eheyden parannukset automatisoituun LPDDR4 muistintestausjärjestelmään

Designing a smart phone requires plenty of testing, tweaking and verification to offer flawlessly functioning high-end products for the customers. Fine-tuning and verifying the memory interface between the application processor and memory, is one important area, which ensures the reliable operation of the device over different operating conditions. Automated testing process reduces the amount of manual measurements, and speeds up the development cycle of the product. However, because of the rising bandwidth (BW) of memories, the signal integrity (SI) properties of the currently used memory testing system have begun to interfere with the device under test (DUT) by causing stability issues. Also, the measured waveforms have not been corresponding to the expected results with the latest memory modules with high data rates and clock speeds. This master’s thesis combines the previous experience and research about the topic, and introduces some new techniques to improve the measurement quality and to minimize the measurement system’s impact to signal properties of DUT. The final goal is to upgrade the previously used automated memory testing system with newly developed techniques to allow good measurement quality with 4 th generation low power double data rate (LPDDR4) memories. In the future, the implemented system is meant to be compatible also with upcoming LPDDR memory generations, with very slight modifications. With implemented memory testing system, there was no more previously mentioned stability issues and measured waveforms matched well to simulations. So at the end, the system performed as expected. There was couple of observations done during the designing and testing process which could improve the system marginally even further but they were not mandatory in terms of system’s operation, and could be implemented easily to next revisions of breakout printed wiring boards (PWB) for memories with different ball grid array (BGA) pinouts

Purjelaivojen mallien konservointi : Kohteena kaksi merimiestyylistä mallia 1800-luvulta

Tässä huonekalukonservoinnin koulutuslinjan opinnäytetyössä käsitellään kahden 1800-luvulta peräisin olevan purjelaivan mallin konservointia. Mallit ovat noin metrin korkeita ja valmistettu puusta. Muita materiaaleja ovat erilaiset takilalangat ja metallikiinnikkeet. Kaikissa osissa on löydettävissä jonkinlainen maali- tai muu pinnoite. Malleissa on paljon pölyä, likaa, irronneita tai osaksi irronneita osia, irronnutta maalipintaa ja katkenneita takilalankoja. Kolmemastoinen malli on selvästi huonommassa kunnossa kuin pienempi kaksimastoinen malli ja tarvitsee enemmän toimenpiteitä. Opinnäytetyön esineistä tiedetään aika vähän ja suurin kysymys onkin: mitä esineet oikein ovat? Esineiden tiedetään olevan Nissasin ratsutilalta, jonka historia tunnetaan 1600-luvulta asti, mutta miksi juuri tällaiset esineet ovat olleet kyseisellä ratsutilalla ja esittävätkö ne kenties jotain oikeita laivoja? Näihin kysymyksiin yritetään löytää vastaus perehtymällä tilan historiaan sekä tilalla asuneeseen Åbergin sukuun. Muita esineisiin liittyvää informaatiota etsitään perehtymällä 1800-luvun purjelaivoihin ja mallirakentamisen historiaan. Opinnäytetyö on pääosin toiminnallinen, sillä purjelaivoja ei ole aikaisemmin konservoitu, ja ainakin suuremmalle mallille toimenpiteiden tarpeellisuus on ilmeinen. Museo toivoo, että mallit saataisiin puhtaiksi, eheiksi ja varastoinnin kannalta kestäviksi. Haluttuun lopputulokseen pääsemiseksi käytetään apuna erilaisia kuvaus- ja analyysimenetelmiä, joiden tulosten perusteella voidaan valita sopivat konservointimetodit. Kuvauksessa laivojen rakennetta tutkitaan röntgenlaitteen avulla ja maalipintojen koostumusta XRF- ja FTIR-analyysein. Konservointitoimenpiteiden näkökulmasta esineet eivät sisällä suuriakaan ongelmia, ja toiminnallisesti pääpaino on esineiden puhdistamisessa ja mastorakenteiden tukemisessa. Vaikka mallit ovat ulkoasultaan hyvin koristelemattomia, on toimenpiteitä vaativien osien määrä huomattavan laaja. Uutta takilalankaa tarvitaan metrejä, ja pintojen tiukka pölykerros vaatii puhdistajaltaan kärsivällisyyttä. Projekti on silti mielenkiintoinen varsinkin jos on kiinnostunut purjelaivoista tai pienoismalleista. Yllättävän mielenkiintoiseksi osoittautui myös Nissasin tila, jonka menneisyyden vaiheet kertovat paljon eteläsuomalaisesta paikallishistoriasta nykyisen Vartiokylän alueella.In this furniture conservation’s thesis are presented the conservation actions done for two ship models from the late 19th century. The models are about one meter tall and they are made from wood. Another materials are different kinds of rigging threads and metal fasteners. All of the parts and surfaces are coated with some kind of paint of surfacing material. The models are very dirty with a lot of dust, dirt, stains, detached or partly detached parts, loosely attached or completely missing paint layers and a lot of broken rigging threads. The bigger model with three masts is in far more worse state than smaller one with two masts. Very little is known about the objects in this thesis and the biggest question is: what type of objects does these models represent? The models are from a farm called Nissas that is located in Vartiokylä on the eastern side of Helsinki. Why have these object been at the farm and do they represent some real ships from 19th century? The answers to these questions are being looked from the history of the Nissas farm and the Åberg family that used to own the farm from 17th century since. More sources of information about the objects is looked from writings and pictures about sailing ships from the 19th century and also from the history of model making. This thesis is mainly functional because there has not been a real conservation actions done to these objects before and the need for the actions, at least for the bigger one, are necessary. The museum wants the objects to become clean, stable and to withstand storing. To get to these goals different kinds of analysis- and photographing methods are being used to help to choose the right materials and procedures for conservation. X-rays are used to see the inner structures of the models and XRF- and FTIR analyses are used to get information about the paint layers. The conservation actions are mainly cleaning the surfaces and supporting the masts. Even though the models are not very decorative the complex rigging and amount of broken parts makes this project very laborious. For somebody interested about sailing ships or models might this project be very fascinating. Also the history of the Nissas farm turned out to be quite an interesting piece of Southern-Finland’s local history

Signaalin eheyden parannukset automatisoituun LPDDR4 muistintestausjärjestelmään

Designing a smart phone requires plenty of testing, tweaking and verification to offer flawlessly functioning high-end products for the customers. Fine-tuning and verifying the memory interface between the application processor and memory, is one important area, which ensures the reliable operation of the device over different operating conditions. Automated testing process reduces the amount of manual measurements, and speeds up the development cycle of the product. However, because of the rising bandwidth (BW) of memories, the signal integrity (SI) properties of the currently used memory testing system have begun to interfere with the device under test (DUT) by causing stability issues. Also, the measured waveforms have not been corresponding to the expected results with the latest memory modules with high data rates and clock speeds. This master’s thesis combines the previous experience and research about the topic, and introduces some new techniques to improve the measurement quality and to minimize the measurement system’s impact to signal properties of DUT. The final goal is to upgrade the previously used automated memory testing system with newly developed techniques to allow good measurement quality with 4 th generation low power double data rate (LPDDR4) memories. In the future, the implemented system is meant to be compatible also with upcoming LPDDR memory generations, with very slight modifications. With implemented memory testing system, there was no more previously mentioned stability issues and measured waveforms matched well to simulations. So at the end, the system performed as expected. There was couple of observations done during the designing and testing process which could improve the system marginally even further but they were not mandatory in terms of system’s operation, and could be implemented easily to next revisions of breakout printed wiring boards (PWB) for memories with different ball grid array (BGA) pinouts